This paper reports the results of a study of changes in the social distribution of mathematics achievement for a cohort of public high school students. Using hierarchical linear modeling (HLM) the study sought to identify school characteristics which were significantly correlated with changes in achievement differences from grade 9 to grade 11 between: (1) white and black students; (2) students from advantaged and disadvantaged socioeconomic backgrounds (SES); and (3) male and female students. The school characteristics considered included indicators of school/community context, school normative climate ("effective schools" indicators), and school instructional setting. While many of the indicators were found to be related to achievement discrepancies at a given point in time, few yielded significant results for changes in the distribution of achievement. School location (suburban), the stability of the student population, and the percentage of low SES children in the school were significant predictors of change over time. It is suggested that effective-schools indicators which are more focused toward equity issues, and those based on student (rather than teacher) input, may be needed if predictors of change are to be found. (Contains 27 references.) (Author)